Gallium nitride-based III-V nitride, which is attracting attention as an excellent blue light emitting element, is put into practical use in light emitting diode field, and expected also as a light pick-up blue-violet semiconductor laser device.
According to Japanese Patent Publication No. 2003-313099A, a heater is provided in a pressure container, a separate reaction container is provided inside of the pressure container, and a crucible is provided inside of the reaction container so that a nitride single crystal is grown by means of flux method.
According to WO 2007-108338A1, in growing GaN single crystal using Na flux, flux and raw material are melted in a crucible to grow GaN signel crystal while it is provided a material absorbing oxygen, such as carbon, outside of the crucible. Oxygen generated from a heater or the like in a pressure container is thereby absorbed to prevent the dissolving of the oxygen into melt.
According to the disclosure of WO 2006-098458A1, a lid is provided in a crucible for containing Na and Ga, and a through hole is formed in the lid and sealed with a material softening at a temperature for the growth. Na and Ga materials in the crucible is not oxidized when the materials are weighed and the crucible is moved, and the material sealing the through hole of the lid is softened and the through hole is opened during the growth. Nitrogen in the atmosphere can be thereby supplied into the inside of the container.
According to the disclosure of WO 2007-108498A1, a heating container is provided in a pressure container, and a heater is provided on the inner wall of the heating container. An inner reaction container is then provided in the heating container and a crucible is provided in the inner reaction container, so that a nitride single crystal of a metal belonging to III group of the periodic table is grown in the crucible. A fitting face is formed between a lid and main body of the heating container and inclined to prevent leakage of hot atmosphere inside of the heating container along the fitting face between the lid and container main body. It is thus possible to reduce temperature gradient in the inner container even under the high pressure and temperature condition required for the growth of the nitride single crystal.